Indicator tube having improved electrode supports

ABSTRACT

The disclosure is of a cold cathode, gas-filled indicator tube which includes an anode electrode and a stack of cathode electrodes in the form of characters which face the sidewall of the envelope as a viewing window. The envelope includes a base or stem which is generally flat and carries tube pins which are connected directly to the lower ends of the cathode electrodes. The upper ends of the cathodes carry tabs which slip into, and are held in, a tray which has an open side and a slotted bottom wall. The tray may be made up of two identical parts, each having an open sidewall for receiving cathode tabs.

United States Patent [56] References Cited UNITED STATES PATENTS 3,026,441 3/1962 Vodden........................

Inventor William M. Hennessey Somerville, NJ. Appl. No. 019,545

3 l 3/260X [22] Filed Mar. 19, 1970 Patemed Feb, 1971 3,437,861 4/1969 KOShlZUka etal............ 313/109.5 [73] Assignee Burroughs Corporation Primary Examiner-R0) Lake Detroit, Mich. Assistant Examiner-David OReilly a corporation of Michigan Attorneys-Kenneth L. Miller and Robert A. Green Continuation of application Ser. No. 743,916, July 3, 1968, now abandoned.

[541 NDICATOR TUBE AWNG IMPROVED ABSTRACT: The disclosure is ofa cold cathode. gas-filled in- ELECTRODE SUPPORTS dicator tube which includes an anode electrode and a stack of 9 Claims sol-wing Figs cathode electrodes in the form of characters which face the sidewall of the envelope as a viewing window. The envelope includes a base or stem which is generally flat and carries tube pins which are connected directly to the lower ends of the cathode electrodes. The upper ends of the cathodes carry tabs which slip into, and are held in, a tray which has an open side and a slotted bottom wall. The tray may be made up of two identical parts, each having an open sidewall for receiving cathode tabs.

PATENTEU FEB 9i9ii 3,562,572

SHEET 1 OF 2 Fig. 1

F ig. '2

INVENTOR. William M. Hennessey ATTORNEY PATENTEDFEB 9|97| 3.562.572 sumenFz Fig.

ZOO 13C) Fig. 5

Fig. 7

INVENTOR. 130 William M. Hennessey 50 ATTORNEY INDICATOR TUBE HAVING IMPROVED ELECTRODE SUPPORTS CROSS REFERENCE TO RELATED APPLICATION This application is a continuation of application Ser. No. 743,916 filed July 3, 1968, now abandoned.

BACKGROUND OF THE INVENTION Indicator tubes of the general type described above have been manufactured successfully and have been used commercially for many years. However,there is an ever-present need to miniaturize and provide structures which will lend themselves to mass production. One problem area concerns the support of the cathode numerals, particularly the upper ends of the cathodes in side view tubes.

SUMMARY OF THE INVENTION Briefly, a display tube embodying the invention includes an anode electrode and a compact stack of cathode electrodes having leads secured to tube pins in the base of the tube and includng a tray means which is of such shape that the upper ends of the cathode numerals can be inserted therein from the side. The lower ends of the cathodes could be supported in the same way, if desired.

DESCRIPTION OF THE DRAWING In the drawing:

FIG. I is a perspective view of a display tube embodying the invention;

FIG. 2 is a sectional elevational view of a portion of the tube of FIG. I showing other cathode numerals;

FIG. 3 is a perspective view of a portion of the support member for the upper cathode tabs;

FIG. 4 is a perspective view of a modification of the support of FIG. 3;

FIG. 5 is a side elevational view of a portion of the tube of FIG. 1;

FIG. 6 is a plan view of a modification of the invention;

FIG. 7 is a perspective view of a portion of the apparatus of FIG. 6; and I FIG. 8 is an elevational view of a modification of a portion of the tube of FIG. 1.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An indicator tube 10 embodying the invention includes an envelope which contains a gas suitable for supporting cathode glow. Such a gas may be argon, neon, or the like, at a pressure which may be in the range of about 30 to about 100 mm. of mercury at insertion. If desired, other substances such as mercury may be added in small quantities to the gas content of the envelope.

The envelope 20 is generally axially elongated, and its sidewall 30 comprises a viewing window through which glowing cathodes 40 may be viewed. The envelope 20 includes a base or stem 50, through which metal pins or leads 60 extend, and by means of which electrical connection is made from the cathode electrodes within the tube to external electrical circuitry. For ease of connection to the cathode electrodes in a miniature tube, the pins 60 are oriented in one or two parallel rows along a diameter of the stem (FIG. 2). At least two other pins 70 (one shown) having glass sleeves 71 are provided at the rear of the stem for connection to the tube anode to be described. The upper end 72 of the envelope carries a tubulation 80 for evacuating the envelope and filling it with the desired gas.

The electrode assembly of tube 10 normally includes a stack of ten cathode electrodes 40 which are in the form of numerals, and a tubular anode electrode which surrounds and encloses the cathode electrodes. The anode electrode includes a solid back plate 90 and a front mesh screen 100 which curve and make electrical contact at the sides of the cathode stack. The two pins 70 are welded to the anode back plate 90. If

desired, another pin may be provided and welded to the front screen to provide added support and for applying operating potential.

Each cathode electrode 40 is of metal and includes a main body portion in the shape of a character and upper andlower tabs 110 and 120, respectively, (FIG. 2), which are used for mounting and supporting the cathodes. In one arrangement, the lower tabs 110 are supported on a horizontal post I22 suitably secured between the anode plate and screen and separated from each other by insulating washers I24. The tabs are welded to tube pins 60, and, in order to prevent the cathode tabs I10 and pins-60 from glowing during tube operation, these members are embedded in a mass 126 of an insulating material, for'example, a glassfn't. Othermasking arrangements might also be used.

The upper cathode tabs are held in place in a novel manner, according to the invention. The arrangement includes an insulating tray 130 which has a solid top wall 140. a solid sidewall 150, an open sidewall I60, and a slotted base 170. The slots are of suitable depth, and they are spaced apart by webs (FIG. 3) or by full walls 192 (FIG. 4) which form separate compartments. The'upper cathode tabs 110 are inserted in these slots or compartments in the tray 130.

The tray 130 is held in place between the rear anode plate 90 and the front anode screen 100 in any suitable fashion, for example, by means of tabs 200 (FIG. 5) which are secured to the anode members and pass through slots in the upper and lower walls of the tray.

In order to prevent the upper cathode tabs from glowing during tube operation, it is desirable to provide a quantity'of an insulating cement 210 (FIG. 2) in the tray toenclose and shield the tabs 120. A'glass frit or a mixture of aluminum oxide and potassium silicate could be used for this purpose.

It can be seen that the tray 130 provides a favorable means for mounting and sealing the upper tabs. It can also be seen that, in mass production operations, the upper cathode tabs can be inserted easily and quickly into the slots 1 80 and into the tray. For such an operation, the leading edges of the webs 190 which define the slots might be 'chamfered to pennit easy entry of the cathode tab.

In another embodiment of the invention (FIGS. 6 and 7), the upper tab support means comprises two identical insulating pieces 201, each of which has an open sidewall 202 and five slots 203 for receiving five of the usual ten cathode tabs. Each piece carries a post 206 at one end and an aperture 208 at the other end, and, when the two pieces are put together as shown, the post of one enters the aperture of the other and any suitable locking means 211 can be secured to each post. The pieces are designed so that, when they are put together, the slots 203 are properly offset to receive a series of cathode tabs. If desired, posts 206 could be separate pieces inserted into aligned apertures in both trays 201.

As shown in FIG. 8, the lower cathode tabs I10 might also be carried in any of the tray configurations described above.

The tube 10 also includes auxiliary character cathodes such as decimal points 260, one of which is shown in FIG. 1.

I claim:

1. A display tube comprising:

an envelope filled with an ionizable gas and having a stem,

a plurality of cathode electrodes mounted in a stack in said envelope,

an anode electrode in said envelope in operative relation with said cathodes,

said cathode electrodes each including a cathode tab by which the cathode is supported, and

mounting means for said cathode tabs including an insulating boxlike tray having an open sidewall, through which the cathode tabs are inserted, and an opposite closed sidewall which limits the insertion depth of said tabs, said tabs being secured by a mass of insulating material.

2. The tube defined in claim 1 wherein said tray includes a bottom wall having a plurality of slots for receiving:

said cathode tabs, and an opposite closed sidewall, and

said slots defining bottom wall ribs which separate said cathode tabs from each other, the depth of said slots determining the insertion depth of said tabs.

3. The tube defined in claim I wherein said tray includes a plurality of parallel walls which divide the tray into compartments, each of which receives a cathode tab and each of which is open at one side and closed on the opposite side.

4. The tube defined in claim 1 wherein each cathode includes an upper cathode tab and a lower cathode tab and said upper cathode tabs are secured in said tray.

5. The tube defined in claim 4 and including an insulating means filling said tray and embedding said cathode tabs.

6. The tube defined in claim 4 and including a second tray similar to said first tray and receiving said lower cathode tabs, the open sidewall of said first tray facing the open sidewall of said second tray, said first tray being thus adapted to receive the tabs of one group of cathodes and vsaid second tray being adapted to receive the cathode tabs of another group of cathodes.

7. A display tube comprising:

an envelope filled with an ionizable gas and having a stem,

a plurality of cathode electrodes mounted in said envelope and each including an upper cathode tab and a lower cathode tab,

a cylindrical anode electrode in said envelope enclosing said cathode electrodes,

an insulating boxlike tray having an open sidewall through which said upper cathode tabs are inserted, and an opposite closed sidewall which limits the insertion depth of said upper cathode tabs, and

said tray beingsupported by said cylindrical anode.

8. The tube defined in claim 1 wherein said mounting means comprises a pair of identical trays having open sidewalls facing each other, each tray receiving selected ones of said cathode tabs, said trays including chambers in which said cathode tabs are adapted to be inserted, the chambers in one tray being of?- set from the chambers in the other tray to receive the tabs of alternate cathodes in said stack.

9. The tube defined in claim 8 and including a pair of posts inserted into apertures in said trays to secure them together. 

1. A display tube comprising: an envelope filled with an ionizable gas and havIng a stem, a plurality of cathode electrodes mounted in a stack in said envelope, an anode electrode in said envelope in operative relation with said cathodes, said cathode electrodes each including a cathode tab by which the cathode is supported, and mounting means for said cathode tabs including an insulating boxlike tray having an open sidewall, through which the cathode tabs are inserted, and an opposite closed sidewall which limits the insertion depth of said tabs, said tabs being secured by a mass of insulating material.
 2. The tube defined in claim 1 wherein said tray includes a bottom wall having a plurality of slots for receiving: said cathode tabs, and an opposite closed sidewall, and said slots defining bottom wall ribs which separate said cathode tabs from each other, the depth of said slots determining the insertion depth of said tabs.
 3. The tube defined in claim 1 wherein said tray includes a plurality of parallel walls which divide the tray into compartments, each of which receives a cathode tab and each of which is open at one side and closed on the opposite side.
 4. The tube defined in claim 1 wherein each cathode includes an upper cathode tab and a lower cathode tab and said upper cathode tabs are secured in said tray.
 5. The tube defined in claim 4 and including an insulating means filling said tray and embedding said cathode tabs.
 6. The tube defined in claim 4 and including a second tray similar to said first tray and receiving said lower cathode tabs, the open sidewall of said first tray facing the open sidewall of said second tray, said first tray being thus adapted to receive the tabs of one group of cathodes and said second tray being adapted to receive the cathode tabs of another group of cathodes.
 7. A display tube comprising: an envelope filled with an ionizable gas and having a stem, a plurality of cathode electrodes mounted in said envelope and each including an upper cathode tab and a lower cathode tab, a cylindrical anode electrode in said envelope enclosing said cathode electrodes, an insulating boxlike tray having an open sidewall, through which said upper cathode tabs are inserted, and an opposite closed sidewall which limits the insertion depth of said upper cathode tabs, and said tray being supported by said cylindrical anode.
 8. The tube defined in claim 1 wherein said mounting means comprises a pair of identical trays having open sidewalls facing each other, each tray receiving selected ones of said cathode tabs, said trays including chambers in which said cathode tabs are adapted to be inserted, the chambers in one tray being offset from the chambers in the other tray to receive the tabs of alternate cathodes in said stack.
 9. The tube defined in claim 8 and including a pair of posts inserted into apertures in said trays to secure them together. 